Sorry I didn't respond to this earlier. I got wrapped up in a DCA debate, which I might add, everyone but me is wrong.
People need to step back for a second and realize that Metrojet is not its own entity that is managed completely separate from US Airways mainline. Why is that important? The reason is that the needs of mainline since it is a bigger moneymaker than MJ can override the needs of MJ. This summer, MJ expansion was drastically slowed because mainline was running out of planes due to labor issues. Thus, flights were cut. These were mostly IAD routes. Since they hadn't been around very long, they had not all matured into big money makers yet. As far as I know, MJ is still beating Southwest at BWI, and no routes were canned. (Read MJ has more of the BWI market share.)
The BOS-MDW flight being cancelled makes everyone think that MJ is very poorly managed. Well, these people need to understand just what it takes to put a route into service. First off, things have to be "pipelined" in order to get it done in a timely manner. This means apply for a gate, prepare to add planes to a fleet or drop other routes, and even announce and book the flight nearly at the same time expecting to complete all other tasks on time. If everything goes as planned, the flight flies full the first day. But what if something goes wrong, like not being able to secure a gate at MDW? You see, Southwest or any other competition had absolutely nothing to do with US not flying this route. But, note the BOS/BDL-Florida routes will remain, at least in the winter. I would not be surprised if they were moved in the summer, because there is much less market for these flights then.
BTW, all airlines are continuously adding and dropping flights. For some reason, people focus on the ones added or dropped by Metrojet as if it is some sort of metric on how well an airline is doing. Go count up how many flight schedules were rearranged at AA or UA or DL recently and compare.